In today’s mobile age, Wireless LANs (WLAN) are critical fixtures in enterprise networks, as employees and visitors alike expect access to an Internet connection from anywhere on your campus. And with BYOD becoming part of the networking vernacular, access is not confined to “traditional,” or authorized, computing platforms, driving up the number of devices on your network and reducing the overall bandwidth available for users.
However, despite the fact that a WLAN is no longer a perk but a requirement in business today, additional resources are rarely allocated for managing this new asset, making the maintenance of ongoing performance and security difficult. Wireless networking presents some unique challenges for the network administrator and requires some new approaches to familiar problems.
Below we will explore five “uniquely wireless” problems, along with the ways that our OmniPeek network analyzer can help you address them.
Managing Signal Strength
One of the fundamental problems with wireless, adequate signal strength, is something completely foreign to wired network connections. Wired “signal strength” is always the same, assuming you have an Ethernet port to connect to. For wireless, signal strength varies with the distance between the user and the access point (AP), and is greatly affected by objects in the path as well as interference from other devices sharing the unlicensed 802.11 spectrum. As signal strength degrades, the data rated used to communicate between the user and the AP decreases, thereby lowering the aggregated data rate for everyone. So, poor signal strength, even for a single client, can be a problem for all WLAN users.
OmniPeek network analyzer measures and reports signal strength in multiple ways, whether for the overall WLAN, for each individual user or AP, or even for each individual packet. It also continually monitors signal strength with its Expert event system, so you don’t have to. Simply set the threshold for the Weak Signal Expert event, and let OmniPeek do the work for you, ensuring adequate signal strength, and over WLAN performance, for all users.
Figure 1 The Weak Signal Strength Expert event in OmniPeek
Managing the Management
Directing traffic in a WLAN is a very complicated task, typically left to the AP. The type and volume of management traffic on a WLAN is significant, and it can tell a great deal about what is going on within the wireless network. And problems on the network often result in greater management traffic, which once again has an adverse effect on the aggregated performance of the WLAN for all users.
OmniPeek analyzes and reports on all 802.11 management traffic, and its Expert event analysis will let you know when there’s too much management going on, along with the likely causes, so you can keep your WLAN performance at its peak performance.
Figure 2 OmniPeek analyzes all 802.11 management data while OmniPeek’s Expert events let you know when excessive WLAN management is causing network issues
Now that we have the signal strength and the management under control, let’s focus on the real reason for even having the WLAN – the users. Wireless networks (infrastructure mode, which is the most common mode) are made up of one or more radio cells, centered on APs. Unlike wired networks, the precise topology of the WLAN changes as clients move around, “roaming” from one AP to the next. The topology can be expressed as a hierarchical tree, with the Extended Service Sets (ESS – all APs connected to the same Distribution System (DS)) at the top, then individual Basic Service Sets (BSS – individual APs and their clients), then the individual client nodes or stations (STAs) themselves.
OmniPeek clearly displays this hierarchical structure, providing detailed information about each station. It also allows you to classify devices as “Trusted,” “Known,” or “Unknown,” making it very easy to spot “rogue,” or unauthorized, devices on your WLAN. In the following screen shot, we clearly have one rogue device on the WP Wireless 1 network.
Figure 3 OmniPeek provides a complete view of the entire WLAN hierarchy
Mobility is a key reason for using a WLAN – users want to be able to move from their office, to the conference room, to the courtyard, and back to their office without network disruption. This activity is called “roaming,” and although 802.11 is designed to address roaming, it does not always happen smoothly or quickly enough, thereby causing unwanted application disruptions, which are especially troublesome in time-sensitive applications like Voice over Wi-Fi.
Analyzing for roaming is a very complex operation. When a user roams, they typically move not only from one AP to another, but also from one channel to another. This requires a WLAN network analysis solution that can monitor and analyze multiple channels simultaneously, not just scanning through channels, but locked onto multiple channels at the same time (for more information, we cover this topic more in depth in our blog titled “The Basics of Wireless Channel Aggregation“. As the user moves from one channel to another, OmniPeek tracks this activity, and reports the time it takes the user to make the transition. Roaming events can simply be logged, or tracked by AP or station, simplifying roaming analysis and quickly identifying problem areas.
Figure 4 OmniPeek provides comprehensive roaming analysis
Managing the Overall User Experience
The wireless side of the network is only part of the entire user experience. Every WLAN is connected to the wired network, and all wireless traffic eventually becomes wired traffic for at least part of its journey. The ability to monitor both the wireless and wired side of a network, simultaneously, can help solve many critical WLAN issues, like user authentication, which depends on verification of user credentials on the wired side of the network when the most secure WLAN security is employed (WPA-2, which should be the only choice on enterprise networks).
OmniPeek analyzes both wired and wireless networks, and can analyze multiple networks simultaneously, making it an ideal solution for tracking user data across the entire network. As business critical applications use the WLAN more and more, it will be more than authentication issues that require full network access for troubleshooting.
Figure 5 OmniPeek captures both wired and wireless network traffic, simultaneously, and automatically compares data to draw attention to critical issues, like too many wireless retransmissions
The demand for wireless networks is ever increasing and as technology continues to rapidly evolve, the performance of your WLAN depends on active, informed network management and analysis. Wireless networks no longer grow organically; they are modeled and designed to exacting standards based on the requirements of your applications and users. You need a WLAN analysis and management solution that touches all the bases, from design to verification to deployment, ensuring that configuration, coverage, performance, and end-to-end network operations meet those exacting standards.
Given the dynamic nature of wireless, you should approach your WLAN proactively and be sure to continually monitor all aspects of the network once deployed. OmniPeek’s Expert event analysis allow you to do this automatically, constantly monitoring your WLAN for trouble and only alerting you when trouble is brewing.